Air conditioning/ventilating system

ABSTRACT

The ventilating air-conditioning system includes an air supply fan; an exhaust fan; a compressor; a first heat exchanger heat-exchanging between outdoor air sent from the air supply fan and a refrigerant; an expansion mechanism; a second heat exchanger heat-exchanging between air in a sanitary space sent by the exhaust fan and a refrigerant; and a refrigerant circuit piped so that a refrigerant circulates in order of the compressor, first heat exchanger, expansion mechanism, and second heat exchanger, or in order of the compressor, second heat exchanger, expansion mechanism, and first heat exchanger. The system heats or cools an indoor space while ventilating a sanitary space by transferring heat between the first heat exchanger and second heat exchanger through a refrigerant.

TECHNICAL FIELD

The present invention relates to a ventilating air-conditioning system using a heat pump to ventilate and to air-condition a sanitary space such as a bathroom.

BACKGROUND ART

With a conventional ventilating air-conditioning system such as for a bathroom using a heat pump, one heat exchanger of the heat pump discharges or absorbs heat to or from air introduced from an indoor space other than the bathroom. With some systems, the air is blown out into the bathroom, and at the same time the other heat exchanger of the heat pump discharges or absorbs heat to or from air discharged from the bathroom to the outdoors to air-condition the bathroom during ventilation (refer to patent literature 1, for instance).

With other systems, the heat pump is separated into outdoor and indoor units, and a heat exchanger placed in the outdoor unit discharges or absorbs heat to or from outdoor air. A heat exchanger placed in the indoor unit discharges or absorbs heat to or from air in the bathroom to air-condition the bathroom, and a ventilating blower placed in the indoor unit ventilates the bathroom (refer to patent literature 2, for instance).

With yet other systems, an indoor heat pump unit separated from the outdoor unit is provided with a sensible heat exchange ventilation element, which sensibly heat-exchanges during ventilation (refer to patent literature 3, for instance).

As described above, various types of ventilating air-conditioning systems are devised such as for a bathroom using a heat pump. The bathroom air-conditioning system exemplified in patent literature 1 recovers heat from air discharged from the bathroom to the outdoors during ventilation to condition air in an indoor space other than the bathroom and to supply the air into the bathroom. In this case, outdoor air flows into the indoor space other than the bathroom to cause the following problems. That is, comfort is impaired due to such as draft feeling; mold grows due to condensation near a natural air inlet; and a wall surface becomes dirty due to dust in outdoor air.

-   [Patent literature 1] Japanese Patent Unexamined Publication No.     2005-180712 -   [Patent literature 2] Japanese Patent Unexamined Publication No.     2002-349930 -   [Patent literature 3] Japanese Patent Unexamined Publication No.     H09-53840

SUMMARY OF THE INVENTION

A ventilating air-conditioning system of the present invention includes an air supply fan that draws in outdoor air through an air inlet open to the outdoors and blows out the outdoor air through an air outlet open to an indoor space; an exhaust fan that draws in air in a sanitary space through an inlet open to the sanitary space and blows out the air in the sanitary space through an air outlet open to the outdoors; a compressor that compresses a refrigerant; a first heat exchanger that heat-exchanges between outdoor air sent by the air supply fan and the refrigerant; an expansion mechanism that expands the refrigerant; a second heat exchanger that heat-exchanges between air in the sanitary space sent by the exhaust fan and the refrigerant; and a refrigerant circuit piped so that the refrigerant circulates in order of the compressor, first heat exchanger, expansion mechanism, and second heat exchanger, or in order of the compressor, second heat exchanger, expansion mechanism, and first heat exchanger. The system transfers heat between the first and second heat exchangers through the refrigerant to heat or cool the indoor space while ventilating the sanitary space.

Such a ventilating air-conditioning system prevents outdoor air not conditioned from flowing into an indoor space, thereby improving comfort, preventing mold from growing due to condensation near a natural air inlet, and preventing a wall surface from becoming dirty due to dust in outdoor air.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a sketch of an indoor space where a ventilating air-conditioning system according to an embodiment of the present invention is placed.

FIG. 2 is a configuration diagram of the air path of the ventilating air-conditioning system.

FIG. 3 is a diagram of the refrigerant circuit of the ventilating air-conditioning system.

FIG. 4 is a working diagram of the ventilating air-conditioning system.

FIG. 5 is an outline block diagram of the refrigerant heater of the ventilating air-conditioning system.

FIG. 6 is an outline sectional view of the refrigerant-water heat exchanger of the ventilating air-conditioning system.

REFERENCE MARKS IN THE DRAWINGS

-   -   1 Indoor space     -   3 Bathroom     -   4 Washroom     -   5 Toilet     -   6 Sanitary space     -   7 Main body     -   8 Exhaust outlet     -   10 Air supply inlet     -   12 Air outlet     -   14 Exhaust fan     -   16 Air inlet     -   17 Air supply fan     -   18 Air-conditioner     -   20 Exhaust air path     -   23 Supply air path     -   26 First heat exchanger     -   27 Auxiliary heater     -   28 Preheater     -   29 Second heat exchanger     -   31 Air path changing/adjusting unit     -   32 Air supply bypass     -   33 Exhaust bypass     -   34 Dehumidification changer     -   35 Drain unit     -   36 Drain pump     -   38 Heat insulator     -   39 Refrigerant circuit     -   40 Compressor     -   41 Expansion mechanism     -   42 Flow path changing valve     -   43 First bypass circuit     -   44 Second bypass circuit     -   45 First open/close valve     -   46 Second open/close valve     -   47 Refrigerant heater unit     -   48 Open/close mechanism     -   49 Capillary tube     -   51, 52 Coil temperature sensor     -   59 Refrigerant heater     -   66 Refrigerant-water heat exchanger     -   67 Water heater

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

Hereinafter, a description is made of an embodiment of the present invention with reference to the related drawings.

Exemplary Embodiment

FIG. 1 is a sketch of an indoor space where a ventilating air-conditioning system according to an embodiment of the present invention is placed. Indoor space 1 is partitioned into living room 2; and sanitary space 6 such as bathroom 3, washroom 4, and toilet 5. The roof space of bathroom 3 is provided therein with main body 7 of the ventilating air-conditioning system.

Main body 7 is connected to exhaust duct 9 communicating between main body 7 and exhaust outlet 8 open to the outdoors; air supply duct 11 communicating between main body 7 and air supply inlet 10 open to the outdoors; and air outlet duct 13 communicating between main body 7 and air outlet 12 open to the ceiling of living room 2.

FIG. 2 is a configuration diagram of the air path of the ventilating air-conditioning system of the present invention. Main body 7 has exhaust fan 14 disposed therein, and exhaust fan 14 is provided with exhaust connection unit 19 connecting exhaust duct 9 at the air outlet side of exhaust fan 14. Main body 7 has exhaust air path 20 formed therein communicating between exhaust connection unit 19 and air inlet 16 of grill 15 placed in the ceiling surface of bathroom 3. Hence, operating exhaust fan 14 causes air in bathroom 3 to be drawn into exhaust fan 14 through air inlet 16 and to be discharged to the outdoors through exhaust duct 9.

Main body 7 has air supply fan 17 disposed therein, and air supply fan 17 has air supply connection unit 21 connecting air supply duct 11 provided at the inlet side of air supply fan 17. Air supply fan 17 has air outlet connection unit 22 connecting air outlet duct 13 provided at the air outlet side of air supply fan 17, and main body 7 has supply air path 23 communicating between air supply connection unit 21 and air outlet connection unit 22 formed inside main body 7. Hence, operating air supply fan 17 causes outdoor air to be drawn into air supply fan 17 through air supply duct 11 and to be blown out to living room 2 through air outlet duct 13.

Then, continuously operating exhaust fan 14 and air supply fan 17 causes fresh outdoor air to be supplied into living room 2, and the outdoor air flows into bathroom 3 through louvers or an undercut of the door to bathroom 3. Then, vapor and smell in bathroom 3 are drawn through air inlet 16 of grill 15 and discharged to the outdoors.

The air supply and exhaust operation needs to be continuously performed for a building with high hermeticity (24-hour ventilation). Exhaust fan 14 and air supply fan 17 are continuously operated so that a predetermined amount (e.g. approximately a half volume of indoor space 1 per hour) of air supply and exhaust is secured. Living room 2 has air-conditioner 18 placed therein for controlling the room temperature, which appropriately maintains the temperature of the room through cooling operation in summer or heating operation in winter. Hence as described above, with year-round continuous ventilating operation, low-temperature air cooled by air-conditioner 18 in living room 2 is drawn into air inlet 16 through louvers or an undercut of the door to bathroom 3 in summer; and high-temperature air heated, in winter. Then, the cooled or heated air is discharged to the outdoors through main body 7 of the ventilating air-conditioning system.

The bottom of main body 7 of the ventilating air-conditioning system has air inlet 16 therein of grill 15 open to the ceiling surface of bathroom 3, and air inlet 16 has an indoor filter (not shown) detachably disposed thereon for collecting dust.

The inside of supply air path 23 is provided at its upstream side from air supply fan 17 with supply air open/close device 24 opening and closing supply air path 23 (the degree of opening is adjustable); detachable outdoor filter 25 for collecting outdoor dust; and first heat exchanger 26 heat-exchanging mainly between outdoor air and a refrigerant, in order starting from air supply connection unit 21. At the downstream side from air supply fan 17, auxiliary heater 27 heating at least part of outdoor air sent by air supply fan 17 is provided.

The inside of exhaust air path 20 is provided at its upstream side from exhaust fan 14 with preheater 28 preheating air drawn from bathroom 3; and second heat exchanger 29 heat-exchanging mainly between the drawn air and the refrigerant, in order starting from air inlet 16. At the downstream side from exhaust fan 14, exhaust open/close device 30 opening and closing exhaust air path 20 (the degree of opening is adjustable) is provided.

Supply air path 23 is provided therein with air path changing/adjusting unit 31 communicating or blocking between the upstream side of first heat exchanger 26 and the upstream side of second heat exchanger 29 in exhaust air path 20, or adjusting the amount of communication.

Supply air path 23 is provided therein with air supply bypass 32 blowing part of the outdoor air into living room 2 not through first heat exchanger 26. Exhaust air path 20 is provided therein with exhaust bypass 33 discharging part of the bathroom air to the outdoors not through second heat exchange 29.

Exhaust air path 20 is provided therein with dehumidification changer 34 communicating or blocking between the downstream side from second heat exchanger 29 and the upstream side from first heat exchanger 26 in supply air path 23, or adjusting the amount of communication.

Supply air path 23 and exhaust air path 20 are provided on their bottoms with drain unit 35 inclined at its bottom, for draining or vaporizing a large amount of dew condensation water generated in the first and second heat exchangers after the water is temporarily stored. Drain unit 35 is provided at its deepest part with drain pump 36 for draining water stored in drain unit 35, thereby allowing the water to be drained to a position higher than main body 7 through drain piping 37.

The outer shell of main body 7 including supply air path 23 and exhaust air path 20 is heat-insulated with heat insulator 38 stuck to the outer shell.

FIG. 3 is a diagram of the refrigerant circuit of the ventilating air-conditioning system according to the embodiment of the present invention. Main body 7 is provided therein with refrigerant circuit 39 filled with a refrigerant such as any one of an HCFC refrigerant (contains atoms of chlorine, hydrogen, fluorine, and carbon in molecules); an HFC refrigerant (contains atoms of hydrogen, carbon, and fluorine in molecules); and a natural refrigerant (e.g. hydrocarbon, carbon dioxide). Refrigerant circuit 39 includes compressor 40 compressing a refrigerant; first heat exchanger 26; expansion mechanism 41 composed of an electronic expansion valve expanding the refrigerant; and second heat exchanger 29.

Refrigerant circuit 39 includes a path (heating cycle, hereinafter) through which a refrigerant compressed by compressor 40 passes in order of first heat exchanger 26, expansion mechanism 41, and second heat exchanger 29, and then returns to compressor 40. Refrigerant circuit 39 includes a path (cooling cycle, hereinafter) through which a refrigerant compressed by compressor 40 passes in order of second heat exchanger 29, expansion mechanism 41, first heat exchanger 26, and then returns to compressor 40. Further, refrigerant circuit 39 is provided with flow path changing valve 42 changing between the heating cycle and cooling cycle.

Refrigerant circuit 39 is provided with first bypass circuit 43 split from the piping connecting flow path changing valve 42 to first heat exchanger 26, and joining the piping connecting expansion mechanism 41 to second heat exchanger 29. Refrigerant circuit 39 is provided with second bypass circuit 44 split from the piping connecting first heat exchanger 26 to flow path changing valve 42, and joining the piping connecting second heat exchanger 29 to flow path changing valve 42. First bypass circuit 43 is provided with first open/close valve 45 opening and closing first bypass circuit 43, and second bypass circuit 44 is provided with second open/close valve 46 opening and closing second bypass circuit 44 and refrigerant heater unit 47 heating a refrigerant. For refrigerant heater unit 47, refrigerant heater 59 shown in FIG. 5 and refrigerant-water heat exchanger 66 shown in FIG. 6 can be used.

First heat exchanger 26 is placed in supply air path 23; second heat exchanger 29, in exhaust air path 20. Hence, the refrigerant discharges or absorbs heat mainly to or from outdoor air sent by air supply fan 17, in first heat exchanger 26; mainly to or from air discharged from bathroom 3 to the outdoors by exhaust fan 14, in second heat exchanger 29.

The piping through which a refrigerant in first heat exchanger 26 flows is equipped with decompression unit 50 composed of open/close mechanism 48 and capillary tube 49. When flow path changing valve 42 changes the flow direction of the refrigerant to the heating cycle shown by the solid line, outdoor air sent by air supply fan 17 heat-exchanges with a refrigerant flowing through first heat exchanger 26 at the downstream side from decompression unit 50. After that, the outdoor air heat-exchanges with a refrigerant flowing at the upstream side from decompression unit 50.

Further, the inside of exhaust air path 20 is provided at its upstream side from second heat exchanger 29 with preheater 28 having self temperature controllability. Activating preheater 28 causes air drawn from bathroom 3 into exhaust air path 20 to be heated and to be supplied to second heat exchanger 29.

First heat exchanger 26 and second heat exchanger 29 are provided at their expansion mechanism 41 side with coil temperature sensors 51, 52 detecting the temperature of a refrigerant.

In this way, the ventilating air-conditioning system according to the embodiment of the present invention thus transfers heat through a refrigerant between first heat exchanger 26 and second heat exchanger 29, and heats or cools indoor space 1 while ventilating sanitary space 6 such as bathroom 3.

FIG. 4 is a working diagram of the ventilating air-conditioning system according to the embodiment of the present invention. Hanging hook 54 of main body 7 is hung on bolt 53 placed at the roof space to suspend main body 7 so as not to contact the ceiling surface. With the ventilating air-conditioning system of FIG. 4, air drawn from bathroom 3 is assumed to be conveyed into main body 7 through inlet duct 55, which is different from the configuration of FIG. 2.

Main body 7 is connected to air outlet duct 13, air supply duct 11, and exhaust duct 9 for conveying air, and is connected to drain piping 37 for draining dew condensation water and power line 56 for supplying electric power.

Further, main body 7 is provided therein with refrigerant circuit 39 sequentially linking at least compressor 40, flow path changing valve 42, first heat exchanger 26, expansion mechanism 41, and second heat exchanger 29. Compressor 40 has two rotors and is placed in a horizontal position to reduce vibration of main body 7 and to decrease the height of main body 7.

Main body 7 includes vibration isolator 57 to further absorb vibration of compressor 40, and bolt 53 includes vibration isolator 58 to suppress vibration propagating to the frame of main body 7.

FIG. 5 is an outline block diagram of the refrigerant heater of the ventilating air-conditioning system according to the embodiment of the present invention. Refrigerant heater 59 is composed of refrigerant pipe line 60 made of refrigerant piping coiled for conducting a refrigerant; electrothermal tube 61 placed in a U-shaped form at the inner circumferential side of coiled refrigerant pipe line 60; and heat transfer cylinder 65 formed in a solid cylinder-shaped form by casting a metallic material (e.g. aluminum) so as to cover all the surface except inlet 62 and outlet 63 of refrigerant pipe line 60; and terminals 64 of electrothermal tube 61.

When a predetermined voltage is applied between terminals 64 of electrothermal tube 61, electrothermal tube 61 generates heat, which then transfers through the inside of heat transfer cylinder 65 to heat refrigerant pipe line 60 disposed on the outer circumference of electrothermal tube 61. The refrigerant is introduced into refrigerant pipe line 60 through inlet 62. In the process of the refrigerant flowing through the coiled part of refrigerant pipe line 60 where its outer circumference is covered with heat transfer cylinder 65, the refrigerant is heated through heat transfer cylinder 65, and then led to outlet 63. Electrothermal tube 61 placed at the core of heat transfer cylinder 65 generates heat toward refrigerant pipe line 60 placed in the outer circumferential direction of heat transfer cylinder 65, and thus a small amount of heat leaks outside. Heat generated by electrothermal tube 61 transfers through heat transfer cylinder 65 to uniformly heat refrigerant pipe line 60, thereby improving the heating efficiency and downsizing refrigerant heater unit 47.

FIG. 6 is an outline sectional view of the refrigerant-water heat exchanger of the ventilating air-conditioning system according to the embodiment of the present invention. Refrigerant-water heat exchanger 66 has a dual-pipe structure, with refrigerant pipe line 69 (through which a refrigerant flows) disposed inside hot-water pipe line 68 (through which hot water from water heater 67 flows). Refrigerant pipe line 69 is split into two parts inside hot-water pipe line 68, and formed in a twisted manner (split refrigerant pipe line 69 is helically twisted), thereby increasing the heat transfer area to improve the heat exchange efficiency.

Next, the hot water that has flown from hot-water flow-in part 70 of hot-water pipe line 68 into refrigerant-water heat exchanger 66 flows through the outer circumference of refrigerant pipe line 69; flows out from hot-water flow-out part 71 outside refrigerant-water heat exchanger 66; and then drops into drain unit 35 underneath hot-water flow-out part 71. Drain unit 35 doubles as a drain tray for dew condensation water generated at first heat exchanger 26 and second heat exchanger 29. The hot water that has dropped into drain unit 35 is drained together with drain water outside main body 7 through drain piping 37 by drain pump 36. In this way, hot water that has heat-exchanged with the refrigerant is drained through drain unit 35.

Meanwhile, the refrigerant that has flown into refrigerant-water heat exchanger 66 from refrigerant flow-in part 74 of refrigerant pipe line 69 faces the flow of hot water to split into twisted tube 75. Here, the refrigerant is heated by heat exchange with the hot water and flows out through refrigerant flow-out part 76. The hot water used for heating the refrigerant may be heated by whichever type of water heater: combustion or heat pump. A heat pump water heater, using atmospheric heat, further improves the heating efficiency of refrigerant heater unit 47 and lowers the running cost.

Still, with a structure that returns water discharged from hot-water flow-out part 71 to water heater 67, hot-water pipe line 68 can be supplied with circulating water for heating, not with hot water heated by water heater 67.

Instead, hot-water pipe line 68 may be supplied with normal-temperature feed water directly, not with high-temperature water heated by a water heater. In this case, with flow path changing valve 42 changed to the cooling cycle and second open/close valve 46 set to the open state, refrigerant circuit 39 is supplied with a high-temperature, high-pressure refrigerant compressed by compressor 40, which enables the refrigerant to be cooled in a process of heat exchange with normal-temperature water such as tap water. In this way, refrigerant-water heat exchanger 66 may be supplied with normal-temperature water to be made heat-exchange with the refrigerant.

Next, a description is made of operation of the ventilating air-conditioning system. Tables 1, 2 list operating states in each operation pattern.

[Table 1]

[Table 2]

The lists of tables 1, 2 describe each operation pattern of the ventilating air-conditioning system in sequence column-wise, and operating states of main components in each operation pattern are described row-wise. As shown in the lists, this ventilating air-conditioning system can execute 10 different operation patterns: heat-exchanging ventilation operation, air supply/exhaust operation, air supply operation, exhaust operation, dehumidification operation, heating operation, cooling operation, heat-exchanging ventilation operation while slightly dehumidifying, heat-exchanging ventilation operation while slightly heating, and heat-exchanging ventilation operation while slightly cooling.

The heat-exchanging ventilation operation is an operation pattern in which, while rapidly discharging smell and moisture in sanitary space 6, heat of air conditioned by such as air-conditioner 18 when outdoor fresh air is supplied into indoor space 1 is recovered into a refrigerant when exhausting; air supplied from the outdoors is heated by the refrigerant; and the air is supplied with its temperature and humidity brought to those of conditioned air in indoor space 1. In this operation, exhaust fan 14 is set to “strong notch” (capable of rapid exhaust); air path changing/adjusting unit 31 is set to the air supply/exhaust position (exhaust air path 20 and supply air path 23 are secured, shown in the figure); and air supply fan 17 is set to “strong notch” (capable of supplying air of the same amount as exhaust).

Air supply bypass 32, exhaust bypass 33, and dehumidification changer 34 are all set to the closed state; auxiliary heater 27 and preheater 28, to the stop state; and air supply open/close device 24 and exhaust open/close device 30, to the open state.

In refrigerant circuit 39, compressor 40 is operated at the lowest frequency (extremely low power consumption); flow path changing valve 42 is retained in the heating state in winter and in the cooling state in summer, according to the difference between outdoor and indoor temperatures, for instance; and expansion mechanism 41 is adjusted to an appropriate degree of opening for an optimum refrigeration cycle when needed. Open/close mechanism 48 is set to the open state, and thus the refrigerant does not pass through capillary tube 49. Refrigerant heater unit 47 is set to the stop state; and first open/close valve 45 and second open/close valve 46, to the closed state.

In winter in this state, for instance, exhaust fan 14 is operated at “strong notch”. A large volume of air warmed by air-conditioner 18 in indoor space 1 passes through a hallway and/or the undercut of a door and travels through exhaust air path 20 from air inlet 16 of grill 15 placed in the ceiling together with air containing smell and moisture in sanitary space 6. Fin-tube-type second heat exchanger 29 that has been changed to a “vaporizer” by flow path changing valve 42 exhausts air with its heat absorbed into the refrigerant to the outdoors through exhaust open/close device 30, exhaust connection unit 19, exhaust duct 9, and exhaust outlet 8. Then, operating air supply fan 17 at “strong notch” makes a large volume of outdoor, cold, fresh air be drawn into supply inlet 10 and pass through air supply duct 11, air supply connection unit 21 of main body 7, air supply open/close device 24, outdoor filter 25, and supply air path 23. In first heat exchanger 26 that has been changed to a “condenser” as a result that the heating state is retained by flow path changing valve 42, a refrigerant compressed and conveyed by compressor 40 discharges heat into cold air from the outdoors including heat absorbed from air in second heat exchanger 29 (i.e. “vaporizer”). Consequently, cold air from the outdoors, becoming warm, is blown out from air outlet 12 to living room 2 through air outlet connection unit 22 and air outlet duct 13.

The refrigerant is changed to a gas of relatively low pressure and temperature by compressor 40 operated at the lowest frequency; discharged in a small circulation amount; and enters first heat exchanger 26 through flow path changing valve 42. With open/close mechanism 48 in the open state, the refrigerant discharges heat into a large volume of air from the outdoors at the entire first heat exchanger 26 to decrease its temperature, becoming a low-temperature liquid. Further, the refrigerant is decompressed by expansion mechanism 41 to enter a two-phase state with low pressure and low temperature; absorbs heat from a large volume of air in indoor space 1 at second heat exchanger 29, becoming a low-pressure, low-temperature gas; and then returns to compressor 40.

Moisture in sanitary space 6 condenses into dew condensation water on the fins of second heat exchanger 29 (i.e. “vaporizer”) and flows down to drain unit 35. The accumulated dew condensation water is drained through drain piping 37 to such as the outdoors and a catch basin by operation of drain pump 36. Alternatively, the dew condensation water is sprayed onto first heat exchanger 26 (i.e. “condenser”), and vaporized and exhausted when air in sanitary space 6 is heat-exchanged.

Meanwhile, the insulation effect of heat insulator 38 around main body 7 prevents condensation and performance deterioration.

In summer, a large volume of air cooled by air-conditioner 18 in indoor space 1 enters main body 7 together with air containing smell and moisture in sanitary space 6; absorbs heat from the refrigerant at second heat exchanger 29 that has been changed to a “condenser” by flow path changing valve 42; and then discharged to the outdoors. Then, a large volume of outdoor, hot, fresh air enters main body 7; discharges heat to the refrigerant at first heat exchanger 26 that has been changed to a “vaporizer” as a result that the cooling state is retained by flow path changing valve 42; and is cooled and blown out into living room 2.

In this way, as a result that compressor 40 is operated at the lowest frequency, the refrigerant circulates to first heat exchanger 26 and second heat exchanger 29 with low power consumption; as a result that exhaust fan 14 and air supply fan 17 are operated at “strong notch”, a large volume of air is exhausted and supplied, which results in the heat-exchanging ventilation operation in which the heat of exhaust from indoor space 1 is recovered and discharged into the supplied air.

Next, a description is made of operation when the air supply/exhaust operation is performed. The operation is an operation pattern in which a ventilating air volume regulated by the Building Standards Law is secured for 24 hours and indoor space 1 is supplied with air while sanitary space 6 is exhausted. When the air supply/exhaust operation is performed, exhaust fan 14 is set to “weak notch” (low power consumption); air path changing/adjusting unit 31, to the air supply/exhaust position (exhaust air path 20 and supply air path 23 are secured, shown in the figure); and air supply fan 17, to “strong notch” (capable of supplying air of the same amount as exhaust).

Air supply bypass 32 and exhaust bypass 33 are set to the open state; dehumidification changer 34, to the closed state; auxiliary heater 27 and preheater 28, to the stop state; and air supply open/close device 24 and exhaust open/close device 30, to the open state.

Refrigerant circuit 39 stops compressor 40 to prevent a refrigerant from flowing, and thus flow path changing valve 42, expansion mechanism 41, open/close mechanism 48, refrigerant heater unit 47, first open/close valve 45, and second open/close valve 46 are all set to the stop state.

In an intermediate season (e.g. spring, autumn) in this state, for instance, exhaust fan 14 operates at “weak notch”, which causes air in indoor space 1 containing such as VOC generated from building materials and furniture to pass through a hallway and/or the undercut of a door. Then, the air travels through air inlet 16 of grill 15 placed in the ceiling of sanitary space 6, exhaust air path 20, mainly exhaust bypass 33 in the open state, exhaust open/close device 30, exhaust connection unit 19, exhaust duct 9, and exhaust outlet 8, and is discharged to the outdoors. Meanwhile, as a result that air supply fan 17 is operated at “weak notch”, outdoor fresh air enters air supply inlet 10 and passes through air supply duct 11, air supply connection unit 21 of body 7, air supply opening and closing device 24, outdoor filter 25, and supply air path 23. Then, the outdoor fresh air passes through mainly air supply bypass 32 in the open state, air outlet connection unit 22, and air outlet duct 13, and is blown out from air outlet 12 into living room 2.

In this way, operating exhaust fan 14 and air supply fan 17 at “weak notch” results in the air supply/exhaust operation in which a small volume of air in indoor space 1 is discharged with extremely low power consumption and outdoor air is supplied.

Next, a description is made of operation when the air supply operation is performed. The operation is an operation pattern in which indoor space 1 is merely supplied with air when outdoor air provides more comfortable temperature and humidity or when outdoor air is cleaner than indoor. When the air supply operation is performed, exhaust fan 14 is stopped; air path changing/adjusting unit 31 is set to the air supply/exhaust position (exhaust air path 20 and supply air path 23 are secured, the state shown in the figure); and air supply fan 17 is operated at “weak notch” (low power consumption).

Air supply bypass 32 and exhaust bypass 33 are set to the open state; dehumidification changer 34, to the closed state; auxiliary heater 27 and preheater 28, to the stop state; and air supply open/close device 24 and exhaust open/close device 30, to the open state.

Refrigerant circuit 39 stops compressor 40 to prevent the refrigerant from flowing, and thus flow path changing valve 42, expansion mechanism 41, open/close mechanism 48, refrigerant heater unit 47, first open/close valve 45, and second open/close valve 46 are all set to the stop state.

In an intermediate season (e.g. spring, autumn) in this state, for instance, as a result that air supply fan 17 is operated at “weak notch”, outdoor fresh air enters air supply inlet 10. Then, the outdoor fresh air passes through air supply duct 11, air supply connection unit 21, air supply open/close device 24, outdoor filter 25, and supply air path 23 of main body 7; through mainly air supply bypass 32 in the open state; through air outlet connection unit 22 and air outlet duct 13; and then is blown out from air outlet 12 into living room 2.

In this way, operating air supply fan 17 at “weak notch” results in the air supply operation in which a small volume of outdoor air is supplied with extremely low power consumption.

Next, a description is made of operation when the exhaust operation is performed. The operation is an operation pattern in which sanitary space 6 is merely exhausted such as when the environment in indoor space 1 is not changed largely. When the exhaust operation is performed, air supply fan 17 is stopped; air path changing/adjusting unit 31 is set to the air supply/exhaust position (exhaust air path 20 and supply air path 23 are secured, the state shown in the figure); and exhaust fan 14 is operated at “weak notch” (low power consumption).

Air supply bypass 32 and exhaust bypass 33 are set to the open state; dehumidification changer 34, to the closed state; auxiliary heater 27 and preheater 28, to the stop state; and air supply open/close device 24 and exhaust open/close device 30, to the open state.

Refrigerant circuit 39 stops compressor 40 to prevent the refrigerant from flowing, and thus flow path changing valve 42, expansion mechanism 41, open/close mechanism 48, refrigerant heater unit 47, first open/close valve 45, and second open/close valve 46 are all set to the stop state.

In an intermediate season (e.g. spring, autumn) in this state, for instance, exhaust fan 14 operates at “weak notch”, which causes air in indoor space 1 containing such as VOC generated from building materials and furniture to pass through a hallway and/or the undercut of a door. Then, the air in indoor space 1 travels through air inlet 16 of grill 15 placed in the ceiling of sanitary space 6, exhaust air path 20, mainly exhaust bypass 33 in the open state, exhaust open/close device 30, exhaust connection unit 19, exhaust duct 9, and exhaust outlet 8, and is discharged to the outdoors.

In this way, operating exhaust fan 14 at “weak notch” results in the air exhaust operation in which a small volume of air in sanitary space 6 is discharged with extremely low power consumption.

Next, a description is made of operation when the dehumidification operation is performed. The operation is an operation pattern used when reheating and dehumidifying indoor space 1 to improve comfort against high humidity during a rainy season or against humidification by households and to restrain mold on such as a wall surface. To perform the dehumidification operation, exhaust fan 14 is stopped; air path changing/adjusting unit 31 is set to the air supply/exhaust position” (exhaust air path 20 and supply air path 23 are secured, the state shown in the figure). During the dehumidification operation, dehumidification changer 34 is set to the open state in which exhaust air path 20 communicates with supply air path 23; air supply open/close device 24 and exhaust open/close device 30 are set to the closed state; and air supply fan 17 is operated at “strong notch”.

Air supply bypass 32 and exhaust bypass 33 are set to the closed state; and auxiliary heater 27 and preheater 28, to the stop state.

Refrigerant circuit 39 operates the compressor at a frequency adjusted according to the temperature and humidity of the air drawn into indoor space 1; retains flow path changing valve 42 to the heating state; and adjusts expansion mechanism 41 to an appropriate degree of opening for an optimum refrigeration cycle when needed. Open/close mechanism 48 is set to the open state, and thus the refrigerant does not pass through capillary tube 49. Refrigerant heater unit 47 is set to the stop state; and first open/close valve 45 and second open/close valve 46, to the closed state.

In this state, as a result that exhaust open/close device 30 and air supply open/close device 24 are in the closed state and dehumidification changer 34 in the open state, exhaust air path 20 is in a negative pressure when air supply fan 17 operates at “strong notch”. A large volume of air containing much moisture in indoor space 1 passes through a hallway and/or the undercut of a door, and flows into exhaust air path 20 from air inlet 16 of grill 15 placed in the ceiling together with air in sanitary space 6. After that, the large volume of air containing much moisture in indoor space 1 is heat-absorbed and dehumidified by the refrigerant at fin-tube-type second heat exchanger 29 that has been changed to a “vaporizer” by flow path changing valve 42, and flows into supply duct 23. Then the large volume of air containing much moisture in indoor space 1 is heated at first heat exchanger 26 that has been changed to a “condenser”. The dehumidified air, being warmed, travels through air outlet connection unit 22, air outlet duct 13, and is blown out from air outlet 12 into living room 2.

The refrigerant is changed to a gas of moderately high pressure and temperature by compressor 40 operating at an appropriate frequency and is discharged to enter first heat exchanger 26 through flow path changing valve 42. With open/close mechanism 48 in the open state, the refrigerant discharges heat into a large volume of air (its temperature and humidity have been lowered by second heat exchanger 29) sent from indoor space 1 to lower its temperature, changing into a low-temperature liquid at first heat exchanger 26. Further, the refrigerant is decompressed by expansion mechanism 41 to enter a two-phase state with low pressure and low temperature; absorbs heat from a large volume of air in indoor space 1 at second heat exchanger 29, becoming a low-pressure, low-temperature gas; and then returns to compressor 40.

Moisture in sanitary space 6 condenses into dew condensation water on the fins of second heat exchanger 29 (i.e. “vaporizer”) and flows down to drain unit 35. The accumulated dew condensation water is drained through drain piping 37 to such as the outdoors and a catch basin by operation of drain pump 36.

Meanwhile, the insulation effect of heat insulator 38 around main body 7 prevents condensation and performance deterioration.

In this way, as a result that compressor 40 is operated at an appropriate frequency, the refrigerant circulates to first heat exchanger 26 and second heat exchanger 29. As a result that air supply fan 17 is operated at “strong notch” with exhaust open/close device 30 and air supply open/close device 24 in the closed state and with dehumidification changer 34 in the open state, the dehumidification operation is performed in which a large volume of air recovers heat when indoor space 1 is dehumidified and reheats indoor space 1.

Next, a description is made of operation when the heating operation is performed. The operation is an operation pattern used to improve comfort by heating indoor space 1 such as in winter or to reduce a heating load on air-conditioner 18. During the heating operation, air path changing/adjusting unit 31 sets supply air path 23 and exhaust air path 20 to the heating/cooling position at which air supplied from the outdoors passes through first heat exchanger 26, and exhaust from indoor space 1 passes through second heat exchanger 29. During the heating operation, exhaust fan 14 and air supply fan 17 are operated at “strong notch”.

Air supply bypass 32, exhaust bypass 33, and dehumidification changer 34 are all set to the closed state; auxiliary heater 27 and preheater 28, to the stop state; and air supply open/close device 24 and exhaust open/close device 30, to the open state.

Refrigerant circuit 39 operates the compressor while adjusting the frequency according to the temperature of the air in indoor space 1 and the outdoors; retains flow path changing valve 42 to the heating state; and adjusts expansion mechanism 41 to an appropriate degree of opening for an optimum refrigeration cycle when needed. Open/close mechanism 48 is set to the open state, and thus the refrigerant does not pass through capillary tube 49. Refrigerant heater unit 47 is set to the stop state; and first open/close valve 45 and second open/close valve 46, to the closed state.

In this state, as a result that exhaust fan 14 is operated at “strong notch”, a large volume of air in indoor space 1 passes through a hallway and/or the undercut of a door, and through exhaust air path 20 from air inlet 16 of grill 15 placed in the ceiling together with air in sanitary space 6. Then, the air that has passed through exhaust air path 20 is heat-discharged from the refrigerant compressed and conveyed by compressor 40, at fin-tube-type first heat exchanger 26 (i.e. “condenser”). The air that has been heat-discharged from the refrigerant passes through air outlet connection unit 22 and air outlet duct 13 by air path changing/adjusting unit 31 set to the heating/cooling position, and is blown out from air outlet 12 into living room 2. Then, as a result that air supply fan 17 is operated at “strong notch”, a large volume of outdoor air enters air supply inlet 10 and passes through air supply duct 11, air supply connection unit 21 of main body 7, air supply open/close device 24, outdoor filter 25, and supply air path 23. The large volume of outdoor air is retained in the heating state by air path changing/adjusting unit 31 set to the heating/cooling position; heat-absorbed by the refrigerant at second heat exchanger 29 that has been changed to a “vaporizer”; and discharged to the outdoors through exhaust open/close device 30, exhaust connection unit 19, exhaust duct 9, and exhaust outlet 8.

The refrigerant is changed to a gas of high pressure and temperature by compressor 40 operating at an appropriate frequency, and is discharged to enter first heat exchanger 26 through flow path changing valve 42. With open/close mechanism 48 in the open state, the refrigerant discharges heat into a large volume of air sent from indoor space 1 to lower its temperature at entire first heat exchanger 26, changing into a low-temperature liquid. Further, the refrigerant is decompressed by expansion mechanism 41 to enter a two-phase state with low pressure and low temperature; absorbs heat from a large volume of outdoor air at second heat exchanger 29, becoming a low-pressure, low-temperature gas; and then returns to compressor 40.

Outdoor moisture condenses into dew condensation water on the fins of second heat exchanger 29 (i.e. “vaporizer”) and flows down to drain unit 35. The accumulated dew condensation water is drained through drain piping 37 to such as the outdoors and a catch basin by operation of drain pump 36.

Meanwhile, the insulation effect of heat insulator 38 around main body 7 prevents condensation and performance deterioration.

In this way, as a result that compressor 40 is operated at an appropriate frequency, the refrigerant circulates to first heat exchanger 26 and second heat exchanger 29. As a result that air path changing/adjusting unit 31 is retained at the heating/cooling position, and exhaust fan 14 and air supply fan 17 are operated at “strong notch”, a large volume of air is warmed, which results in the heating operation in which indoor space 1 is heated.

Further, auxiliary heater 27 can be switched between on and off according to preferences of the user. For instance, if the user feels a draft feeling and sets the system so as to reduce the air volume of air supply fan 17, the refrigerant discharges less heat as the air volume supplied to first heat exchanger 26 decreases although draft feeling decreases, which lowers the temperature of indoor space 1 to impair comfortable feeling. If auxiliary heater 27 is operated in such a case, the air that has passed through first heat exchanger 26 is further heated by auxiliary heater 27, and the high-temperature air is supplied to indoor space 1, thereby suppressing a decrease of the room temperature.

When outdoor air temperature is extremely low in winter, the temperature of outdoor air supplied to second heat exchanger 29 by exhaust fan 14 is also low, and thus a frosting phenomenon occurs in which frost forms on second heat exchanger 29 while the above-described heating operation is performed. If this frosting state is left, the amount of heat discharge at first heat exchanger 26 decreases as the heat-absorbing performance of second heat exchanger 29 decreases, resulting in indoor space 1 not adequately heated. To suppress such a problem, defrosting operation 1 needs to be performed in which the temperature of the refrigerant piping of second heat exchanger 29 is monitored by coil temperature sensor 52 during the heating operation, and frost formed on second heat exchanger 29 is removed when the temperature decreases below a predetermined level. Next, a description is made of operation when defrosting operation 1 is performed.

When performing defrosting operation during heating operation, exhaust fan 14 that has been operated at “strong notch” and air supply fan 17 that has been operated at “predetermined notch” are stopped, and flow path changing valve 42 that has been set to the heating state is changed to the cooling operation. With such setting being made, a high-temperature, high-pressure refrigerant compressed by compressor 40 passes through flow path changing valve 42 that has been changed to cooling and is led to second heat exchanger 29. As a result that this high-temperature refrigerant flows through the refrigerant piping of second heat exchanger 29, the temperature of the piping rises to dissolve frost formed on the surface. The dissolved frost becomes drain water; drops down to drain unit 35; and is drained to such as the outdoors and a catch basin through drain pump 36 and drain piping 37.

Meanwhile, the refrigerant that has discharged heat and dissolved frost at second heat exchanger 29 flows through expansion mechanism 41, first heat exchanger 26, and path changing valve 42 in sequence, and returns to compressor 40 to circulate in refrigerant circuit 39. If this defrosting operation 1 is continued, the frost formed on second heat exchanger 29 dissolves completely and the temperature of the piping continues to rise. This temperature of the piping is continuously monitored by coil temperature sensor 52, and the pattern is changed from defrosting operation 1 to the heating operation again when the temperature of the piping rises above a predetermined level. Then, operation of exhaust fan 14 that has been stopped is started at “strong notch”; the temperature of the refrigerant is monitored by coil temperature sensor 51 placed on the piping at the liquid side of first heat exchanger 26; and operation of air supply fan 17 is also started at “predetermined notch” when a certain level of temperature is reached. This operation prevents the heating performance from excessively deteriorating at low temperature, allowing sufficient heating.

If defrosting is needed when the outdoor temperature is extremely low or the temperature in indoor space 1 is low, instead of defrosting operation 1 in which heating operation is once stopped and frost is removed by changing to defrosting operation, another defrosting operation is requested in which frost formed on second heat exchanger 29 is removed while continuing heating operation. Next, a description is made of such defrosting operation 2.

In defrosting operation 2, exhaust fan 14, air supply fan 17, compressor 40, flow path changing valve 42, open/close mechanism 48, and the others all continue operation for heating operation. Then, first open/close valve 45 and second open/close valve 46 are changed from the closed state to the open state; the electronic expansion valve of expansion mechanism 41 is set to the fully closed state; and preheater 28 and refrigerant heater unit 47 are respectively operated. As a result that the settings are thus changed, a high temperature, high-pressure refrigerant compressed by compressor 40 passes through flow path changing valve 42 set to heating, and with first open/close valve 45 having been changed to the open state, the refrigerant is split into first heat exchanger 26 and first bypass circuit 43. The refrigerant diverted to first heat exchanger 26 discharges heat into the air in indoor space 1 supplied from air supply fan 17, and the air heated by the heat discharge of the refrigerant circulates in indoor space 1 to continue heating operation.

Meanwhile, as a result that the electronic expansion valve as expansion mechanism 41 is set to the fully closed state, and second open/close valve 46 interposed in second bypass circuit 44 is set to the open state, all the refrigerant flows through second bypass circuit 44 and flows into refrigerant heater unit 47. Refrigerant heater unit 47 is provided with refrigerant heater 59 or refrigerant-water heat exchanger 66 as described above and heats the refrigerant to perform heat-absorbing operation.

On the other hand, the high-temperature, high-pressure refrigerant discharged from compressor 40 and diverted to first bypass circuit 43 flows into second heat exchanger 29. As a result that exhaust fan 14 is operated at “strong notch”, second heat exchanger 29 is supplied with outdoor air through air supply inlet 10 and air supply duct 11.

Then, the refrigerant that has dissolved frost at second heat exchanger 29 merges with the refrigerant heated by refrigerant heater unit 47 to returns to compressor 40 through flow path changing valve 42. After the air supplied to second heat exchanger 29 provides heat to the frost formed, the air is discharged to the outdoors through exhaust duct 9. In this way, second heat exchanger 29 can be defrosted while continuing heating indoor space 1. Then, the temperature of the piping of second heat exchanger 29 is monitored by coil temperature sensor 52 for a level higher than a predetermined value, and when the temperature rises to the level, namely when removing the frost completes, regular heating operation is resumed, allowing continuous heating operation without impairing comfortable feeling of users.

Next, a description is made of operation when the cooling operation is performed. The operation is an operation pattern used to lower the temperature in indoor space 1 at high temperature such as in summer to cool indoor space 1 for comfort or to reduce a cooling load on air-conditioner 18. To perform this cooling operation, air path changing/adjusting unit 31 is set to the heating/cooling position at which exhaust air path 20 and supply air path 23 are arranged so that the air supplied from the outdoors passes through first heat exchanger 26 and exhaust from indoor space 1 passes through second heat exchanger 29; and exhaust fan 14 and air supply fan 17 are operated at “strong notch”.

Air supply bypass 32, exhaust bypass 33, dehumidification changer 34 are all set to the closed state; auxiliary heater 27 and preheater 28, to the stop state; and air supply open/close device 24 and exhaust open/close device 30, to the open state.

Refrigerant circuit 39 operates the compressor while adjusting the frequency according to the temperature of the air in indoor space 1 and the outdoors; retains flow path changing valve 42 to the cooling state; and adjusts expansion mechanism 41 to an appropriate degree of opening for an optimum refrigeration cycle when needed. Open/close mechanism 48 is set to the open state, and thus the refrigerant does not pass through capillary tube 49. Refrigerant heater unit 47 is set to the stop state; and first open/close valve 45 and second open/close valve 46, to the closed state.

In this state, as a result that air supply fan 17 is operated at “strong notch”, a large volume of outdoor air enters air supply inlet 10 and passes through air supply duct 11, air supply connection unit 21 of main body 7, air supply open/close device 24, outdoor filter 25, and supply air path 23. The large volume of outdoor air is retained in the cooling state and absorbs heat from the refrigerant compressed and conveyed by compressor 40 at fin-tube-type second heat exchanger 29 that has been changed to a “condenser”. Then, the air is discharged to the outdoors through exhaust open/close device 30, exhaust connection unit 19, exhaust duct 9, and exhaust outlet 8 by air path changing/adjusting unit 31 set to the heating/cooling position.

Meanwhile, as a result that exhaust fan 14 is operated at “strong notch”, a large volume of air in indoor space 1 passes through a hallway and/or the undercut of a door, and passes through exhaust air path 20 from air inlet 16 of grill 15 placed in the ceiling together with air in sanitary space 6. Then, the air that has been heat-absorbed and cooled by the refrigerant at first heat exchanger 26 that has been changed to a “condenser” passes through air outlet connection unit 22 and air outlet duct 13 by air path changing/adjusting unit 31 set to the heating/cooling position, and is blown out from air outlet 12 into living room 2.

Then, the refrigerant is changed to a gas of high pressure and temperature by compressor 40 operating at an appropriate frequency and is discharged to enter first heat exchanger 29 through flow path changing valve 42, and discharges heat into a large volume of outdoor air to lower its temperature. The refrigerant is decompressed by expansion mechanism 41 to enter a two-phase state with low pressure and low temperature, becoming a low-temperature liquid. With open/close mechanism 48 in the open state, the refrigerant absorbs heat from a large volume of air sent from indoor space 1 to lower its temperature at entire first heat exchanger 26, becoming a low-pressure, low-temperature gas; and then returns to compressor 40 through flow path changing valve 42.

Moisture in indoor space 1 condenses into dew condensation water on the fins of first heat exchanger 29 (i.e. “vaporizer”) and flows down to drain unit 35. The accumulated dew condensation water is drained through drain piping 37 to such as the outdoors and a catch basin by operation of drain pump 36. Instead, the dew condensation water is sprayed onto second heat exchanger 29 (i.e. “condenser”), and is vaporized and discharged when heat-exchanging the outdoor air.

Meanwhile, the insulation effect of heat insulator 38 around main body 7 prevents condensation and performance deterioration.

In this way, as a result that compressor 40 is operated at an appropriate frequency, the refrigerant circulates to second heat exchanger 29 and first heat exchanger 26. As a result that air path changing/adjusting unit 31 is retained at the heating/cooling position; and exhaust fan 14 and air supply fan 17 are operated at “strong notch”, a large volume of air is cooled, which results in the cooling operation in which indoor space 1 is cooled.

Next, a description is made of operation when the slightly dehumidifying heat-exchanging ventilation is performed. The operation is an operation pattern for recovering heat of air conditioned such as by air-conditioner 18 to a refrigerant when supplying indoor space 1 with outdoor fresh air while rapidly discharging smell and moisture in sanitary space 6; and reheating and dehumidifying indoor space 1 while heating air supplied from the outdoor and sending the air, to improve comfort against high humidity during a rainy season or against humidification by households and to restrain mold on such as a wall surface.

During this operation, exhaust fan 14 and air supply fan 17 are operated at “strong notch” while adjusting air path changing/adjusting unit 31 to an appropriate degree of opening between the heating/cooling position and the air supply/exhaust position (the state shown in the figure). Then, adjustment is made for each air volume of outdoor air passing through first heat exchanger 26 and second heat exchanger 29; and that in indoor space 1. Here, the heating/cooling position of air path changing/adjusting unit 31 refers a state in which exhaust air path 20 and supply air path 23 are set so that air from the outdoors passes through first heat exchanger 26; and exhaust from indoor space 1, through second heat exchanger 29. The air supply/exhaust position of air path changing/adjusting unit 31 refers a state in which exhaust air path 20 and supply air path 23 are secured.

Air supply bypass 32, exhaust bypass 33, and dehumidification changer 34 are all set to the closed state; auxiliary heater 27 and preheater 28, to the stop state; and air supply open/close device 24 and exhaust open/close device 30; to the open state.

Refrigerant circuit 39 operates compressor 40 while adjusting the frequency according to the temperature and humidity of the air in indoor space 1 and the outdoors; retains flow path changing valve 42 to the heating state; and sets expansion mechanism 41 to the fully open state. Open/close mechanism 48 is set to the closed state and passes the refrigerant flow through capillary tube 49 to be decompressed; the upstream side of first heat exchanger 26 from capillary tube 49 is used as a “condenser”; and the downstream, as a “vaporizer”. Refrigerant heater unit 47 is set to the stop state; and first open/close valve 45 and second open/close valve 46, to the closed state.

In this state, as a result that air supply fan 17 is operated at “strong notch”, a large volume of air in indoor space 1 passes through a hallway and/or the undercut of a door, and passes through exhaust air path 20 from air inlet 16 of grill 15 placed in the ceiling together with air in sanitary space 6. A large volume of outdoor air passes through air supply duct 11. The air flows merge with their air volumes adjusted by air path changing/adjusting unit 31 having been set to “adjusting the degree of opening”. The air merged is dehumidified at the downstream side from capillary tube 49, of first heat exchanger 26 that has been set to the heating state by flow path changing valve 42 to become a “vaporizer”; and reheated at the upstream side from capillary tube 49, of first heat exchanger 26 that has become a “condenser”. The air dehumidified and reheated is blown out from air outlet 12 into living room 2 through air outlet connection unit 22 and air outlet duct 13.

Then, as a result that exhaust fan 14 is operated at “strong notch”, a large volume of outdoor air enters air supply inlet 10 and passes through air supply duct 11, air supply connection unit 21 of main body 7, air supply open/close device 24, outdoor filter 25, and supply air path 23. Meanwhile, a large volume of air in indoor space 1 passes through exhaust air path 20 from air inlet 16 of grill 15. The air flows merge with their air volumes adjusted by air path changing/adjusting unit 31 having been set to “adjusting the degree of opening”. The air merged is heat-absorbed by the refrigerant at second heat exchanger 29 retained in the heating state by flow path changing valve 42 to become a “vaporizer”; and discharged to the outdoors through exhaust open/close device 30, exhaust connection unit 19, exhaust duct 9, and exhaust outlet 8.

The refrigerant is changed to a gas of high pressure and temperature by compressor 40 operating at an appropriate frequency and is discharged to enter first heat exchanger 29 through flow path changing valve 42. With open/close mechanism 48 in the closed state, the refrigerant discharges heat into a large volume of air in indoor space 1 and from the outdoors, at the upstream side from capillary tube 49, of first heat exchanger 26 to decrease its temperature, entering a two-phase state with medium-low temperature. Further, the refrigerant is decompressed at capillary tube 49, entering a two-phase state with medium-low pressure and medium-low temperature. Next, the refrigerant slightly absorbs heat from a large volume of air in indoor space 1 and from the outdoors at the downstream side of first heat exchanger 26 from capillary tube 49, entering a two-phase state with medium-low pressure and medium-low temperature. With decompression mechanism 41 in the fully open state, the refrigerant is slightly decompressed to enter second heat exchanger 29 (i.e. “vaporizer”); further absorbs heat from a large volume of air from the outdoors and indoor space 1, becoming a low-pressure, low-temperature gas; and returns to compressor 40.

Moisture in indoor space 1 and the outdoors condenses into dew condensation water at the downstream part of first heat exchanger 26 (i.e. “vaporizer”) from capillary tube 49 and on the fins of second heat exchanger 29, and flows down to drain unit 35. The accumulated dew condensation water is drained through drain piping 37 to such as the outdoors and a catch basin by operation of drain pump 36.

Meanwhile, the insulation effect of heat insulator 38 around main body 7 prevents condensation and performance deterioration.

In this way, as a result that compressor 40 is operated at an appropriate frequency, the refrigerant circulates to the upstream part of first heat exchanger 26 from capillary tube 49, capillary tube 49, the downstream part from capillary tube 49, and second heat exchanger 29. Air path changing/adjusting unit 31 is retained at “adjusting the degree of opening”; and exhaust fan 14 and air supply fan 17 are operated at “strong notch”, which results in the slightly dehumidifying heat-exchanging ventilation, in which heat in indoor space 1 is recovered to be reheated and dehumidified; and sanitary space 6 is exhausted and supplied with outdoor air.

Next, a description is made of operation when the slightly heating heat-exchanging ventilation is performed. The operation is an operation pattern for recovering heat of air conditioned such as by air-conditioner 18 when supplying indoor space 1 with outdoor fresh air while rapidly discharging smell and moisture in sanitary space 6; and heating indoor space 1 while heating air supplied from the outdoor and sending the air, to improve comfort in winter or to reduce a heating load on air-conditioner 18.

During this operation, exhaust fan 14 and air supply fan 17 are operated at “strong notch” while adjusting air path changing/adjusting unit 31 to an appropriate degree of opening between the heating/cooling position and the air supply/exhaust position (the state shown in the figure). Then, adjustment is made for each air volume of outdoor air passing through first heat exchanger 26 and second heat exchanger 29; and that in indoor space 1. The other operation is the same as that of the heating. Here, the heating/cooling position of air path changing/adjusting unit 31 refers a state in which exhaust air path 20 and supply air path 23 are set so that air from the outdoors passes through first heat exchanger 26 and exhaust from indoor space 1 passes through second heat exchanger 29. The air supply/exhaust position of air path changing/adjusting unit 31 refers a state in which exhaust air path 20 and supply air path 23 are secured.

Next, a description is made of operation when the slightly cooling heat-exchanging ventilation is performed. The operation is an operation pattern for recovering heat of air conditioned such as by air-conditioner 18 when supplying indoor space 1 with outdoor fresh air while rapidly discharging smell and moisture in sanitary space 6; and for cooling indoor space 1 with the refrigerant absorbing heat from air supplied from the outdoors, to improve comfort in summer or to reduce a cooling load on air-conditioner 18.

During this operation, exhaust fan 14 and air supply fan 17 are operated at “strong notch” while adjusting air path changing/adjusting unit 31 to an appropriate degree of opening between the heating/cooling position and the air supply/exhaust position (the state shown in the figure). Then, adjustment is made for each air volume of outdoor air passing through first heat exchanger 26 and second heat exchanger 29; and that in indoor space 1. The other operation is the same as that of the cooling. Here, the heating/cooling position of air path changing/adjusting unit 31 refers a state in which exhaust air path 20 and supply air path 23 are set so that air from the outdoors passes through first heat exchanger 26 and exhaust from indoor space 1 passes through second heat exchanger 29. The air supply/exhaust position of air path changing/adjusting unit 31 refers a state in which exhaust air path 20 and supply air path 23 are secured.

With the configuration and operation described hereinbefore, the ventilating air-conditioning system according to the embodiment of the present invention presents the following effects.

The system transfers air through a refrigerant between first heat exchanger 26 and second heat exchanger 29; and heats or cools outdoor air to supply indoor space 1 with the air by air supply fan 17 while discharging air in bathroom 3 by exhaust fan 14. This operation prevents outdoor air not conditioned from flowing into indoor space 1, thereby improving comfort, preventing mold from growing due to condensation near a natural air inlet, and preventing a wall surface from becoming dirty due to dust in outdoor air. Further, with heat exchange between air and the refrigerant by the heat exchanger, saving energy is totally achieved including reducing running costs of air-conditioner 18. The low pressure loss of the heat exchanger increases the air volume for ventilating.

Air path changing/adjusting unit 31 adjusts each amount of outdoor air passing through first heat exchanger 26 and second heat exchanger 29; and that in the sanitary space to balance each amount of ventilation air, exhaust, and supply air according to environmental conditions such as indoor and outdoor temperature, indoor and outdoor humidity, and the pollution level of indoor air. This operation allows supplying indoor space 1 with air while ventilating sanitary space 6, which allows air-conditioning with low energy.

The system sets air supply bypass 32 of first heat exchanger 26 and exhaust bypass 33 of second heat exchanger 29 to the open state during ventilation to supply and discharge air between indoor space 1 and the outdoors without passing part of air in the outdoors and sanitary space 6 through first heat exchanger 26 and second heat exchanger 29. This operation allows supplying indoor space 1 with air and exhausting sanitary space 6 with lower power for the same air volume of supply and exhaust.

The system changes the air path so that air drawn from sanitary space 6 is cooled at second heat exchanger 29; reheated at first heat exchanger 26; and blown out into indoor space 1, thereby reducing temperature changes in indoor space 1 and dehumidifying indoor space 1 while reducing heat flowing out to the outdoors.

Flow path changing valve 42 changes the direction in which the refrigerant flows, which allows switching between heating and cooling in indoor space 1.

The system operates so that air drawn from the outdoors is cooled at the downstream side of first heat exchanger 26 from decompression unit 50, reheated at the upstream side from decompression unit 50, and then blown out into indoor space 1, which allows dehumidifying indoor space 1 without excessively decreasing the temperature in indoor space 1 while introducing outdoor fresh air into indoor space 1.

When heating, cooling, or dehumidifying indoor space 1, the system increases the air volume of air supply fan 17 or exhaust fan 14, unlike when ventilating sanitary space 6, thereby increasing the performance of recovering heat, and ventilating and air-conditioning with lower power consumption.

Air conditioned by air-conditioner 18 placed at a location other than sanitary space 6 enters air inlet 16 to sanitary space 6, and the heat of the air is recovered. Hence, heat is used of the air blown out from air-conditioner 18 more efficient than the ventilating air-conditioning system, thereby downsizing the heat exchanger inside main body 7 and saving energy during air-conditioning operation.

Drain unit 35 arranged under supply air path 23 and exhaust air path 20 reliably disposes of dew condensation water generated in the air path; condensate water from the heat exchanger flows to a single drain outlet to improve workability. Further, an increased amount of water allows the water to flow into the drain outlet smoothly to prevent retained water from developing bacteria.

Operating drain pump 36 allows condensate water or dew condensation water to be drained to a position higher than drain unit 35, thereby enabling the system to be constructed where the drain cannot be sloped adequately due to a small roof space.

Insulating around supply air path 23 and exhaust air path 20 with heat insulator 38 prevents heat from leaking while preventing condensation from forming on the outer shell of main body 7 of the ventilating air-conditioning system, thereby further saving energy.

The inside of main body 7 of the ventilating air-conditioning system placed such as in the roof space of bathroom 3 contains all of compressor 40, first heat exchanger 26, expansion mechanism 41, and second heat exchanger 29 composing refrigerant circuit 39 to save space and to improve workability.

Auxiliary heater 27 heats at least part of the air sent by air supply fan 17, thereby covering deficiency in the heating performance in a low-temperature environment.

Preheater 28 preheats air before being supplied to second heat exchanger 29, thereby restraining the heating performance from decreasing in a low-temperature environment and second heat exchanger 29 from being frosted, as well as removing frost formed.

When frost forms on first heat exchanger 26 or second heat exchanger 29 at low temperature, the system changes flow path changing valve 42 according to the temperature of a refrigerant monitored by coil temperature sensors 51, 52, thereby removing frost formed.

When frost forms on second heat exchanger 29 at low temperature, the system opens the high- and low-pressure sides of refrigerant circuit 39 through first bypass circuit 43 and second bypass 44 to allow a high-temperature refrigerant to circulate to second heat exchanger 29; or increases the refrigerant pressure in second heat exchanger 29, thereby removing frost formed.

Refrigerant heater unit 47 is interposed in refrigerant circuit 39 in series or parallel with second heat exchanger 29; and refrigerant heater unit 47 is activated when the heat-absorbing performance decreases such as due to frost forming on second heat exchanger 29, thereby securing the heat-absorbing performance to maintain the heating performance.

Refrigerant heater unit 47 includes refrigerant heater 59 heating a refrigerant electrothermally, thereby downsizing refrigerant heater unit 47.

Refrigerant heater unit 47 includes refrigerant-water heat exchanger 66 heating a refrigerant by heat exchange with hot water from water heater 67, thereby reducing power usage at refrigerant heater unit 47.

Using hot water heated by a heat pump water heater for hot water to be supplied to refrigerant-water heat exchanger 66 further reduces power usage at refrigerant heater unit 47.

When draining hot water that has undergone heat exchange with a refrigerant by refrigerant-water heat exchanger 66, a drain path is used for draining dew condensation water generated in first heat exchanger 26 and/or second heat exchanger 29, thereby simplifying construction without increasing the number of drain paths.

Arrangement is made so that a refrigerant discharges heat to normal-temperature water supplied to refrigerant-water heat exchanger 66 in case where the discharge heat performance decreases at high temperature such as in summer, thereby resolving deficiency in heat discharge to maintain the cooling performance.

The above description is made only for one embodiment of the present invention, which is not limited to the above embodiment.

For instance, in the above-described embodiment of the present invention, indoor space 1 to be air-supplied and air-conditioned is living room 2; sanitary space 6 having air outlet opening is bathroom 3; however, a space to be air-supplied and air-conditioned and a space having an air outlet opening are not limited to the above, but may be any space as long as it is partitioned within indoor space 1. For instance, a space air-supplied and air-conditioned may be a hallway; a space having an air outlet opening, washroom 4.

In the above-described embodiment of the present invention, air outlet 12 and air inlet 16 respectively open to living room 2 and bathroom 3 one each; however, the numbers of air outlets 12 and air inlets 16 are not limited to the above case. For instance, two air outlets 12 may open to living room 2 and a hallway.

In the above-described embodiment of the present invention, air inlet 16 for exhausting is a cassette-type one provided in grill 15 of main body 7; however, it may be a concealed type one in which a duct is connected to air inlet 16 of main body 7, the end of the duct is connected to another air inlet in the ceiling of a space to be exhausted, and main body 7 is concealed in the roof space.

In the above-described embodiment of the present invention, refrigerant circuit 39 is provided with two-series bypass circuits (first bypass circuit 43 and second bypass circuit 44); however, it may be provided with one-series bypass circuit.

In the above-described embodiment of the present invention, refrigerant heater unit 47 is placed in parallel with second heat exchanger 29; however, it may be interposed in series with second heat exchanger 29 within refrigerant circuit 39.

In the above-described embodiment of the present invention, the configuration is shown in which first open/close valve 45 and second open/close valve 46 are changed between the two levels (open and closed); however, the open/close valve may be any type as long as it opens and closes a bypass circuit such as an electronic expansion valve.

In the above-described embodiment of the present invention, the configuration is shown in which open/close mechanism 48 is placed in parallel with capillary tube 49 as a decompression unit; however, the decompression unit may be any type as long as it can change the decompression action such as a type with an electronic expansion valve interposed.

In the above-described embodiment of the present invention, two types of configurations (i.e. refrigerant heater 59 and refrigerant-water heat exchanger 66) are shown as a concrete configuration of refrigerant heater unit 47; however, refrigerant heater unit 47 may be any type as long as it can heat a refrigerant, not limited to the above-described two types.

In the above-described embodiment of the present invention, the configuration is shown in which the piping at the water side of refrigerant-water heat exchanger 66 is supplied with hot water from a combustion water heater or heat pump water heater; however, the piping may be supplied with high-temperature water (e.g. 40° C. to 90° C.) or normal-temperature feed water (e.g. 1° C. to 40° C.), not limited to hot water from a combustion water heater or heat pump water heater. Any type of water may be used such as hot water or feed water from a gas water heater, electricity water heater, kerosene water heater; circulating water such as for heating floors; normal-temperature city water; or water left in the bathtub.

In the above-described embodiment of the present invention, the motor of air supply fan 17, exhaust fan 14, or compressor 40 is not particularly mentioned (e.g. AC or DC); however, a DC motor particularly saves energy.

In the above-described embodiment of the present invention, compressor 40 has two rotors and is placed in the horizontal position; however, compressor 40 may be scroll-type as long as it is low-vibration type, and may be placed in a vertical position as long as it is low-profile type.

In the above-described embodiment of the present invention, the configuration is shown in which main body 7 is suspended in the roof space of bathroom 3 for installation; however, it may be installed at any location and in any way as long as a space for installing the main body, maintainability, sound insulation, and vibration insulation are secured. For instance, floor-standing main body 7 may be placed in an indoor or outdoor machine room or embedded in a wall surface.

INDUSTRIAL APPLICABILITY

As described above, a ventilating air-conditioning system according to the present invention saves space and improves workability; and recovers heat from the air while rapidly discharging a large volume of air containing moisture and smell generated from a sanitary space. The system air-conditions an indoor space while supplying outdoor fresh air to allow air-conditioning with low energy consumption while improving air quality. Consequently, besides ventilating a sanitary space and air-supplying/air-conditioning an indoor space, the invention is applicable to a ventilating, air-supplying, and air-conditioning system for a living space such as a living room, bedroom, kitchen, and washroom; an uninhabitable space such as a closet, underfloor, and storage; and a nonresidential space such as an office, meeting room, and warehouse.

TABLE 1 Operation pattern Air Heat-exchanging supply/ Air Main component ventilate exhaust supply Exhaust Dehumidify Heat Exhaust fan (14) Strong notch Weak Stop Weak Stop Strong notch notch notch Air path Air supply/ Air Air Air Air supply/ Heat/cool switching/adjusting exhaust position supply/ supply/ supply/ exhaust position unit (31) exhaust exhaust exhaust position position position position Air supply fan (17) Strong notch Weak Weak Stop Strong Strong notch notch notch notch Compressor (40) Lowest Hz Stop Stop Stop Adjust Hz Adjust Hz Flow path Heat or cool Stop Stop Stop Heat Heat changing valve (42) Expansion Adjust degree of Stop Stop Stop Adjust Adjust mechanism (41) opening degree of degree of (electronic opening opening expansion valve) Air supply bypass Closed Open Open Open Closed Closed (32) Exhaust bypass Closed Open Open Open Closed Closed (33) Dehumidification Closed Closed Closed Closed Open Closed changer (34) Auxiliary heater Stop Stop Stop Stop Stop Stop (27) Preheater (28) Stop Stop Stop Stop Stop Stop Refrigerant heater Stop Stop Stop Stop Stop Stop unit (47) Air supply Open Open Open Open Closed Open open/close device (24) Exhaust open/close Open Open Open Open Closed Open device (30) Drain pump (36) Operate Stop Stop Stop Operate Operate Open/close Open Stop Stop Stop Open Open mechanism (48) First open/close Closed Stop Stop Stop Closed Closed valve (45) Second open/close Closed Stop Stop Stop Closed Closed valve (46)

TABLE 2 Operation pattern Slightly dehumidifying Slightly Slightly heat- heating cooling Main exchanging heat-exchanging heat-exchanging component Defrost 1 Defrost 2 Cool ventilate ventilate ventilate Exhaust fan Stop Strong Strong Strong Strong notch Strong (14) notch notch notch notch Air path Heat/cool Heat/cool Heat/cool Adjust Adjust Adjust switching/adjusting position position position degree of degree of degree of unit (31) opening opening opening Air supply fan Stop Strong Strong Strong Strong notch Strong (17) notch notch notch notch Compressor Adjust Hz Adjust Hz Adjust Hz Adjust Hz Adjust Hz Adjust Hz (40) Flow path Cool Heat Cool Heat Heat Cool changing valve (42) Expansion Adjust Fully Adjust Fully open Adjust Adjust mechanism degree of closed degree of degree of degree of (41) (electronic opening opening opening opening expansion valve) Air supply Closed Closed Closed Closed Closed Closed bypass (32) Exhaust Closed Closed Closed Closed Closed Closed bypass (33) Dehumidification Closed Closed Closed Closed Closed Closed changer (34) Auxiliary Stop Operate Stop Stop Stop Stop heater (27) Preheater (28) Stop Operate Stop Stop Stop Stop Refrigerant Stop Operate Stop Stop Stop Stop heater unit (47) Air supply Open Open Open Open Open Open open/close device (24) Exhaust Open Open Open Open Open Open open/close device (30) Drain pump Operate Operate Operate Operate Operate Operate (36) Open/close Open Stop Stop Closed Open Open mechanism (48) First open/close Closed Open Closed Closed Closed Closed valve (45) Second Closed Open Closed Closed Closed Closed open/close valve (46) 

1. A ventilating air-conditioning system comprising: an air supply fan drawing in outdoor air through an air inlet open to outdoors and blowing out the outdoor air through an air outlet open to an indoor space; an exhaust fan drawing in air in a sanitary space through an air inlet open to the sanitary space and blowing out the air in the sanitary space through an air outlet open to the outdoors; a compressor compressing a refrigerant; a first heat exchanger heat-exchanging between the outdoor air sent by the air supply fan and the refrigerant; an expansion mechanism expanding the refrigerant; a second heat exchanger heat-exchanging between air in the sanitary space sent by the exhaust fan and the refrigerant; and a refrigerant circuit piped so that the refrigerant circulates in order of the compressor, the first heat exchanger, the expansion mechanism, and the second heat exchanger, or in order of the compressor, the second heat exchanger, the expansion mechanism, and the first heat exchanger, wherein the system heats or cools the indoor space while ventilating the sanitary space by transferring heat between the first heat exchanger and the second heat exchanger through the refrigerant.
 2. The ventilating air-conditioning system of claim 1, further comprising: a decompression unit decompressing the refrigerant at piping through which the refrigerant in the first heat exchanger flows.
 3. The ventilating air-conditioning system of claim 1, wherein a larger volume of air is sent from the supply fan or the exhaust fan when heating, cooling, or dehumidifying the indoor space than when ventilating the sanitary space.
 4. The ventilating air-conditioning system of claim 1, wherein the indoor space is provided therein with an air-conditioner for controlling temperature of the indoor space, and air in the sanitary space drawn into the air inlet is air conditioned by the air-conditioner.
 5. The ventilating air-conditioning system of claim 1, further comprising: an auxiliary heater heating at least part of the outdoor air sent by the air supply fan.
 6. The ventilating air-conditioning system of claim 1, further comprising: a preheater preheating air drawn in from the sanitary space.
 7. The ventilating air-conditioning system of claim 1, further comprising: a coil temperature sensor detecting temperature of the refrigerant in the first heat exchanger and the second heat exchanger at a side of the expansion mechanism.
 8. The ventilating air-conditioning system of claim 1, further comprising: a supply air path including an air supply connection unit connected to an air supply duct communicating with the air inlet, an air outlet connection unit connected to an exhaust duct communicating with the air outlet, and the first heat exchanger, and communicating between the air supply connection unit and the air outlet connection unit; an exhaust air path including an exhaust connection unit connected to an exhaust duct communicating with the air outlet and the second heat exchanger, and communicating between the exhaust connection unit and the air inlet; and an air path changing and adjusting unit communicating or blocking between an upstream side of the first heat exchanger and an upstream side of the second heat exchanger, or adjusting an amount of communication.
 9. The ventilating air-conditioning system of claim 8, further comprising: an air supply bypass blowing out part of the outdoor air into the indoor space, in the supply air path; and an exhaust bypass discharging part of air in the sanitary space into the outdoors, in the exhaust air path.
 10. The ventilating air-conditioning system of claim 8, further comprising: a dehumidification changer communicating or blocking between a downstream side of the second heat exchanger and a downstream side of the first heat exchanger, or adjusting an amount of communication, in the exhaust air path.
 11. The ventilating air-conditioning system of claim 8, further comprising: a drain unit draining or vaporizing dew condensation water generated in the first heat exchanger and the second heat exchanger, at bottoms of the supply air path and the exhaust air path.
 12. The ventilating air-conditioning system of claim 11, further comprising: a drain pump draining water stored in the drain unit.
 13. The ventilating air-conditioning system of claim 8, wherein the supply air path and the exhaust air path including outer shells thereof are heat-insulated.
 14. The ventilating air-conditioning system of claim 1, further comprising: a flow path changing valve changing a flow direction of the refrigerant from order of the compressor, the first heat exchanger, the expansion mechanism, and the second heat exchanger, to order of the compressor, the second heat exchanger, the expansion mechanism, and the first heat exchanger.
 15. The ventilating air-conditioning system of claim 14, wherein the refrigerant circuit includes: a first bypass circuit splitting from piping connecting the flow path changing valve to the first heat exchanger, and joining piping connecting the expansion mechanism to the second heat exchanger; and a second bypass circuit splitting from piping connecting the first heat exchanger to the expansion mechanism, and joining piping connecting the second heat exchanger to the flow path changing valve, wherein the first bypass circuit includes a first open and close valve opening and closing the first bypass circuit, and the second bypass circuit includes a second open and close valve opening and closing the second bypass circuit.
 16. The ventilating air-conditioning system of claim 15, further comprising: a refrigerant heater unit heating a refrigerant in the second bypass circuit in series or parallel with the second heat exchanger.
 17. The ventilating air-conditioning system of claim 16, wherein the refrigerant heater unit is a refrigerant heater heating the refrigerant by making an electrothermal tube generate heat.
 18. The ventilating air-conditioning system of claim 16, wherein the refrigerant heater unit is a refrigerant-water heat exchanger with a refrigerant pipe line, through which the refrigerant flows, inside a hot-water pipe line through which hot water flows.
 19. The ventilating air-conditioning system of claim 18, wherein hot water used for the refrigerant-water heat exchanger is heated by a heat pump water heater.
 20. The ventilating air-conditioning system of claim 18, wherein the hot water is drained through the drain unit.
 21. The ventilating air-conditioning system of claim 18, wherein the refrigerant-water heat exchanger is supplied with normal-temperature water.
 22. The ventilating air-conditioning system of claim 19, wherein the hot water is drained through the drain unit. 